SU1224299A1 - Method of producing slowly acting granulated fertilizers - Google Patents

Description

The invention relates to the production of mineral fertilizers and relates to a method for the production of slow-acting granulated fertilizers.

The purpose of the invention is to increase the agrochemical properties by reducing the relative rate of fertilizer dissolution and simplifying the process.

Example 1 8 g (4 wt.%) Powdered (ground) elemental sulfur was added to potassium chloride solution and mixed thoroughly. 17.3 ml of water was added and granulated with methane (9 ml) per 100 g of KC1.

The obtained granules are placed in a drying cabinet, where they are heated to 122 ° C and kept at the same temperature for 3 minutes, stirring the granules with a glass rod. At the same time, a thin arm of molten sulfur appears on the surface of the granules. After that, the granules are cooled to room temperature, constantly stirring them.

Example 2. In 192 g of calcium nitrate, 8 g (4 wt.%) Of powdered (ground) elemental sulfur are added. Next, the process is conducted as in example 1.

Example 3. In 192 g of potassium-magnesia, 8 g (4 wt.%) Of powdered (ground) elemental sulfur are added. Next, the process is conducted as described in example 1.

The cooled granules are subjected

I tested the dissolution rate with fertilizer granules,

, obtained by known methods.

The test results are shown in Table. one.

As can be seen from the results given in table. 1, in case of disturbance of the external protective film of sulfur on the granules obtained by the proposed method, the rate of fertilizer dissolution changed insignificantly due to the action of internal protective films, which during impact were only partially disrupted

The rate of dissolution of fertilizers due to the violation of an external protective film of sulfur applied by other known methods (by spraying or dipping into liquid sulfur) increased sharply and practically became equal to the dissolution rate of the granules of these fertilizers obtained without a protective film (without added sulfur).

The elemental sulfur according to the proposed method is introduced not into the water, but into the cris

;

.

ten

20

25

Tall (if you need ground) solid simple or complex fertilizer in powdered (hammer) water. Then the mixture of granular fertilizer with added ground sulfur is subjected to granulation by any known method, for example, by pilling. The obtained granules are heated (dried) to the melting point of sulfur. In this case, the particles of sulfur are melted and moisten (roll) the cristae of the solid bulk fertilizer, forming protective films on them. In addition, by adding a sufficient amount of tS of sulfur (more than 1.5%), molten particles of sulfur form an outer protective sheath. This is clearly seen when cutting the granules formed in this way. The cut is a solid sulfur droplet in which the particles (grains) of fertilizer wetted with solid sulfur are embedded. In this case, the following mechanism of film formation is observed: first, the individual fertilizer grains are moistened with molten sulfur droplets, then the grains covered with a protective film are enveloped with a single protective film over the entire volume of the granule.

The long-term effect of a delayed fertilizer is expressed by a decrease in the average relative rate of fertilizer dissolution compared to the analog and the prototype by more than 3 times.

The determination of the optimum drying temperature and the duration of incubation at this temperature is given in Table. 2

The optimal amount of added sulfur is determined by the boundaries of 2-6 wt.%.

When the amount of sulfur is below 2%, the dissolution rate of the granules remains almost unchanged, i.e. the durability of the fertilizer does not change. When sulfur is added in excess of 10 wt.%, The dissolution rate is compared with the addition of 6 wt.%, I.e. the longevity effect is almost the same. Thus, the addition of more than 6% of sulfur is impractical because it does not affect the agronomic properties and leads to unnecessary costs of sulfur.

As can be seen from the table. 2, the optimum drying temperatures are temperatures ranging from 120-125 ° C (i.e., the melting temperature of sulfur is 119-12Q C or higher than 1-5 ° C).

thirty

35

40

45

50

The optimal exposure time at such temperatures is 2-5 minutes.

Only under such conditions will granules with a strong sulfur film on the surface be obtained. At temperatures below the melting point of sulfur or a top-up time of less than 2 minutes, no sulfur film forms on the surface (sulfur does not melt).

At temperatures above 125 ° C and holding times above 6 min, sulfur flows from the surface of the granule, the granules stick together.

The proposed method is simpler known, since it combines operatives when applying a film-forming substance in a molten form, spraying the granules or dipping the granules, a large amount of film-forming melt J is lost (entrainment during the adhesion, splashing and adhering on the walls of the apparatus and to whom f) x). The sulfur loss in this case is at least 1-2%. 10 In the proposed method, sulfur is introduced in solid powder form, is stored in tanks without heating, is dosed with standard dispensing materials (without heating).

qi of drying and molten sulfur, reduces - is the loss does not exceed 0.5%, with the number of operations, which follows from i. Table 2-6 3.analog.

times below the prototype and

With intact protective film

1. Potassium chloride

2.Kaltsiyeva

With a broken protective film

1. Potassium chloride

2.Kaltsiyev saltpeter

3. Kaliymagnesi

The amount of added sulfur, wt.

24299-

When a film-forming substance is applied in a molten form, by spraying it onto granules or dipping granules, a large amount of film-forming melt is lost (entrainment to the atmosphere during sticking, splashing and sticking on the walls of the apparatus and ficon x). The sulfur loss in this case is at least 1-2%. 10 In the proposed method, sulfur is introduced in solid powdered form, stored in tanks without heating, dispensed with standard dispensing materials (without heating).

volume does not exceed 0.5%

times below the prototype and

Table 1

29

34

27 21

45

47 44

43 23

46 25 40 21

ten

10 7

5 3

1Sulfur no Sulfur not Sulfur on the surface of the granules does not protrude, melts; melts Sulfur forms a film on

2 Sulfur granule surface drains off

surface granules

5Granules stick together

6.Sera abundantly protrudes onto the surface of the granules and flows down from the granule. The granules stick together

I

Analog

Prototype

Sulfur melt

Melt from Ery

Sulfur-free fertilizer granules

Drying gran

Dip pellets in sulfur melt

Pellet cooling

Compiled by R. Gerasimov Editor L. Avramenko Tehred i.Popovich Corrector I. Erdeyi

Order 1889/23

Circulation 419

VNIIPI USSR State Committee

for inventions and discoveries I3035, Moscow, Zh-35, Raushsk nab., 4/5

Fipial PIP Patent, Uzhgorod, st. Project, 4

table 2

The proposed method

one.

Mixing Fertilizer with Sulfur in Powder

Granulation fertilizer with sulfur

Drying the granules at the melting point of sulfur

Pellet cooling

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Claims (2)

1. METHOD FOR PRODUCING SLOW-ACTING GRANULATED FERTILIZERS, including granulation, processing of the obtained granules with sulfur and cooling of the finished product, characterized in that, in order to increase agrochemical properties by reducing the relative dissolution rate of fertilizer and. simplification of the process, sulfur is taken in the form of a powder, which is introduced into the fertilizer before granulation, the obtained granules are heated to the melting point, sulfur, and kept at this temperature 2-5 minutes, and then cooled to a temperature below the melting point of sulfur. 2. The method of pop. 1, distinguishing with the fact that sulfur is introduced into the fertilizer in an amount of 2-6Z by weight of the fertilizer. 1 . 1224299 ²